Ground textures is needed all the time. Its very hard to come by, not to mention very diffictult to create anything remotely acceptable in terms of quality even tho its the most commonly needed texture type.
The following categories would be great:
Dirt / Mud
These are most efficient with Parallax Occlusion Displacement Maps. Bump maps are not enough for natural ground.
Dont do grass textures. Those are a useless waste of time as it would be much better to have them as alphas for billboards/blades.